Deep in the Congo lives a little-studied group of apes called the bonobos. Like chimpanzees, bonobos are among humans' closest relatives. But unlike chimps, known for their violent behavior, bonobos are far more peaceful, even matriarchal. They embrace their neighbors and resolve conflict in an usual way -- by having sex. Much like humans, bonobos have sex not just to procreate, but also for pleasure. The discovery of these more gentle ape traits have fascinated scientists and led them to question our origins and the roots of human nature as a whole.

But in 1997, just as research on these elusive apes was getting off the ground, civil war broke out in the Congo. Bonobo researchers were forced to evacuate immediately, leaving behind the astonishing apes they were studying. Now, years later, "NOVA" returns to the Congo with veteran bonobo researchers who are worried that war and the bush meat industry may have decimated the bonobo population. What they find gives them hope for the future of the species.

The program tells the intimate, emotional story of these amazing apes, detailing their survival, and the experiences of the scientists who have followed them so closely for so long.